Typically, gas turbine engines include a compressor for compressing air, a combustor for mixing the compressed air with fuel and igniting the mixture, and a turbine section including a turbine blade assembly for producing power. The compressor and turbine sections of a turbine engine typically include rotors to which a plurality of blades are attached. The plurality of blades are typically arranged in rows spaced axially along the rotor, Each blade is releasably attached to the periphery of a disc.
FIG. 1 depicts a conventional system for attaching blades 1 to a disc 2. The disc 2, shown in partial section, may have various configurations and includes a disc groove 4 extending about the periphery of the disc 2. Each blade 1 includes a root 6 at a base of the blade 1 that is configured to match the shape of the disc groove 4. Each blade 1 is attached to the disc 2 by sliding the root 6 of each blade 1 into the disc groove 4. The disc groove 4 in the disc 2 enables a plurality of blades 1 to be arranged about the periphery of the disc 1. The blades 1 are spaced apart around the disc 2, and the resulting voids in the disc groove 4 between the roots 6 of adjacent blades 1 are filled with spacers 8. The similarity of the size and shape of the blade root 6 and rotor groove 4 keep the blade 1 attached to the disc 2. In addition, the motion of the blade 1 during normal turbine engine operation creates forces in the axial and radial directions that also restrain the blade 1.
The disc groove 4 typically has lateral recesses 5 for receiving corresponding projections 9 extending from the roots 6 of blades 1 and from spacers 8. Engagement of the recesses 5 and projections 7 secure the blades 1 and spacers 8 axially and radially. The configuration of the projections 7 prevent the blades 1 and spacers 8 from being inserted directly into the disc groove 4 in the operational orientation of the blades 1. Instead, the root 6 of a blade 1 must first be rotated 90 degrees and inserted with the projection 7 extending along the disc groove 4. The blade 1 may then be rotated into the final orientation with the projection 7 extending into the lateral recess 5.
A plurality of blades 1 and spacers 8 may be installed in the disc groove 4 as shown in FIG. 1. Once all of the blades 1 and spacers 8 have been installed and the installation process is nearly complete, the remaining space in the disc groove 4 between adjacent blades may be filled and secured. This open space may not be filled with a conventional spacer 8 because there is not sufficient space remaining in the disc groove 4 to permit insertion and rotation of a spacer 8. Instead, spacers formed from multiple components that can be locked into positioned without being rotated into a final position have been used. In some conventional systems, a multi-piece spacer has been used. However, centrifugal forces encountered during operation of the turbine engine can cause these multi-piece spacers to come apart and cause extensive damage to the turbine engine. Conventional designs often suffer from the devices coming apart if either side of the devices develop clearance relative to adjacent turbine components. Another problem often encountered in conventional designs is that the components forming the conventional design often have problems fitting together. Thus, a need exists for a more efficient and reliable device for filling a void between adjacent turbine components and for securing a final spacer for locking turbine blades to a disc.